Blog about bats in the garden
Allthough most people know me from aquatic and tree surveys 2018 was the year of the bat.
Bats are shy and unknown to many people. Depending on your
cultural background you might associate them with Halloween and scaring people
or, on the positive side with Wu-Fu, Chinese symbol of the five great happinesss:
health, wealth, good luck, long life and tranquillity. Being nocturnal their
live takes place when we go to bed. Often we are not aware if they are visiting
our garden like a robin or blue tit does. All bats in the UK are insectivorous
and use echolocation to find their prey.
species, their breeding sites and resting places are fully protected by
law - they're European protected species.They largely feed on airborne insects, suppress
both naturally occurring and human related-generated insect populations (such
as agricultural pest species and insects that annoy or transmit specific
pathogens to humans and other mammals) and contribute to the maintenance of
ecosystem stability. They are good in finding concentrations of insects. Most
feed on moths in June but smaller species on little bugs and mosquitos as well.
They can eat over a three thousand at one night.
Since 60% of insects are nocturnal as well you might
understand their importance. Evolutionary seen they are very special as well.
They are the only mammals that are capable of self-powered flight. With over
1200 different species they represent a fourth of all mammals species known in
this world. They have developed many niches in for example in foraging, hibernation,
flight, required habitat and roosts. Although very adaptable on an evolutionary
scale most species cant keep up with urbanisation taking place in this world.
Summer 2017 I started to study Ecological Survey Techniques
at Oxford University to expand my survey and research skills. As part of this
study I did a field survey studying bat presence and prey availability in the
urban environment. The study will look at the elements we can influence as
human beings and the role of our gardens for bats in expanding cities.
Conclusions from my study:
Bats were present across all
sites although diversity was low, especially in activity level, and dominated
by only two species; P. pipestrellus and P. pygmaeus. All results, except
for woodland, were directional and only large trees, distance to water and prey
availability showed a significant increase in bat activity. Highly specified
and mobile species require a large set of spatial distribution data, preferably
permanently monitored over a season. Quality
species-specific distribution maps are with this sample size not possible. The attempt to make a garden suitability index that can be
used for further testing in a wider context proved for the above reasons overambitious.
At the sampled gardens, prior
to this survey, only six owners were aware that their garden was visited by
bats. Most were unaware that (garden) lighting causes ecological shifts in
diurnal and nocturnal species. They might have seen P. pipestrellus species feeding near light but did not know
most other bat species are deterred from light. The survey provided the
opportunity to share information about the importance of trees and varied
vegetation height. It created for many their first bat sighting or hearing
experience ever. Although not the purpose of the study a shift in appreciation
of bats and the eco-services they provide is required to gain support for
maintaining important habitat features.
Bats are a bit picky.
They dont like strong winds, cold nights and heavy rain. A bit like most of us
they prefer to stay inside and make that evening unsuitable for surveying. If
the nights get warmer (10 C°+) they will come out of hibernation as soon as the